Spindle and cutting apparatus including the same

Abstract

A spindle includes a housing including a first opening, a bearing housed in the housing, a main shaft rotatably supported by the bearing, a collet chuck in a first through hole defined in the main shaft to grip a machining tool and being movable in an axial direction of the main shaft, a draw bar connected to the collet chuck, and a cover covering the first opening and including a second through hole through which the main shaft is disposed. The main shaft and the cover are disposed at a distance from each other.

What is claimed is: 
     
       1. A spindle comprising:
 a housing including a first opening and a second opening; 
 a bearing housed in the housing; 
 a main shaft rotatably supported by the bearing, the main shaft being provided with a first through hole passing through the main shaft in an axial direction of the main shaft, the main shaft including: 
 a first end located on a first side in the axial direction, located adjacent to the first opening, and extending out of the housing through the first opening; and 
 a second end located on a second side in the axial direction and located adjacent to the second opening; 
 a collet chuck disposed in the first through hole, the collet chuck being movable in the axial direction, the collet chuck including: 
 a first collet end located adjacent to the first end of the main shaft, the first collet end being able to grip a machining tool to machine a workpiece; and 
 a second collet end located on the second side in the axial direction; 
 a draw bar disposed in the first through hole, the draw bar being movable in the axial direction, the draw bar including: 
 a first bar end located adjacent to the first end of the main shaft and connected to the second collet end; and 
 a second bar end located adjacent to the second end of the main shaft; and 
 a cover covering the first opening, the cover being provided with a second through hole through which the main shaft extends; wherein 
 the main shaft and the cover are disposed at a distance from each other; 
 the housing includes:
 an air inlet which is located above the bearing and through which air is introduced into the housing; 
 an air passage through which the air introduced into the housing through the air inlet flows into the second through hole; and 
 an air outlet which is located between the main shaft and a portion of the cover where the second through hole is provided and through which the air inside the housing is discharged out of the housing; 
 
 the spindle further includes a coolant container attached to the housing, the coolant container being provided with a nozzle which is located on the second side in the axial direction with respect to the air outlet and from which a coolant is to be discharged onto the machining tool; 
 a distance between an axis of the main shaft and the air outlet in a radial direction of the main shaft is less than a distance between the air outlet and the nozzle; and 
 a lower end of the nozzle is located inward of an outer edge of the cover in the radial direction of the main shaft. 
 
     
     
       2. The spindle according to  claim 1 , wherein the air outlet opens downward in the axial direction of the main shaft. 
     
     
       3. The spindle according to  claim 1 , wherein the air outlet is located above a lower end of the nozzle. 
     
     
       4. A cutting apparatus comprising:
 the spindle according to  claim 1 ; 
 a unit conveyor to move the spindle in a predetermined direction; 
 a tool magazine that is able to house the machining tool; and 
 a holder connected to the tool magazine to hold the workpiece to be machined with the machining tool.